Method of buffing a metal percussion instrument

ABSTRACT

A buffed metal cymbal or the like percussion instrument is produced by a method in which a surface of the instrument is pressed against a deformable buffing surface moving at high speed at a pressure and for a time period sufficient to produce a shiny buffed finish but insufficient to raise the temperature of the metal enough or to remove sufficient metal to impair the prebuffed tonal quality or resistance to fracture of the instrument.

United States Patent [151 3,640,029 Zildjian Feb. 8, 1972 [54] METHOD OF BUFFING A METAL 2,885,702 5/1959 Way ..l5/97 R PERCUSSION INSTRUMENT Robert Zildjian, Norwell, Mass.

Avedis Zildjian Avedis Company, North Quincy, Mass.

Feb. 16, 1970 Inventor:

Assignee:

Filed:

Appl. No.:

US. CL. ..51/322, 51/317, 134/6 Int. Cl. ..B24b 1/00, B24d 13/08 Field ofSearch ..51/317, 322, 328, 104-106,

References Cited UNITED STATES PATENTS 3,425,080 2/1969 Dolitzsch ..l5/21E 2,469,948 5/1949 Bune ..15/97R Primary ExaminerDonald G. Kelly AtmrneyEdgar I-I. Kent [57] ABSTRACT A buffed metal cymbal or the like percussion instrument is produced by a method in which a surface of the instrument is pressed against a deformable buffing surface moving at high speed at a pressure and for a time period sufficient to produce a shiny buffed finish but insufficient to raise the temperature of the metal enough or to remove sufficient metal to impair the prebuffed tonal quality or resistance to fracture of the instrument.

5 Claims, 4 Drawing Figures wudda METHOD OF BUFFING A METAL PERCUSSION INSTRUMENT This invention relates generally to musical instruments and in particular to novel and improved percussion instruments, especially cymbals and gongs, and a method and apparatus for buffing the surface of such instruments.

As is well known to those skilled in the art, cymbals are generally cast from a tin-copper alloy, rolled in rolling mills to give them the desired diameter and thickness and are cupped and tempered in a press or die. After the center hole is cut the cymbals are cut into a substantially circular shape of the proper diameter by a circle shear and are hammered and peened to define a bowed hub portion and a raised center portion having the circular center hole, for a supporting rod, therethrough. A plurality of tonal grooves of varying depths are cut, generally by means of a turning lathe, in one or both surfaces of the hub portion and spaced at varying distances from the center hole outwardly to the outer edge of the cymbal. The edge is then smoothed. Generally, the cutting of the grooves is among the final steps in the manufacture of cymbals and is followed by aging to provide hardness since the integrity of the grooves must be maintained toinsure that the notes produced by the cymbal when it vibrates have the desired tonal quality.

Prior efforts to buff cymbals in order to give them a highly polished and more pleasant appearance have not produced satisfactory results. Generally, the polishing process is performed manually and on a localized basis-cg, by a hand manipulated buffer or by hand pressing and manipulating the cymbal against a rotating buffing disc, so that only a small portion of a cymbal is polished at one timeand consumes perhaps 30 minutes per cymbal (the total time required depends, of course, on the diameter and, therefore, on the overall surface area of the particular cymbal). The pressure so applied to the cymbal by a buffer over the long time required to polish the surface has been deleterious to the quality of the cymbals in at least two respects. Most importantly, the buffer-to-metal friction has caused the alloy in the cymbal to become excessively hot and to harden and become brittle, resulting in susceptibility of the cymbal to fracture and to deterioration of the quality of the notes produced thereby. In addition, the pressures applied have been such that the buffer has worn the projections between the tonal grooves to such an extent as to damage the tonal quality of the cymbal. As a result, the surfaces of cymbals are not polished but instead arepermitted to retain their relatively dull finish after they have been cast and worked. 7

Accordingly, it is an object of the present invention to provide percussion instruments, especially cymbals, having polished surfaces, without deterioration of the structure or temper of the metal of which they are constructed or of the tonal quality of the instrument, using a new and improved apparatus for and method of buffing such instruments which prevents overheating and wear of the tonal grooves and is simple, and more reliable and much faster than methods attempted to be employed in the past.

Another object of the invention is to provide such a method which may be employed to buff cymbals of different diameters and insures uniformity in the buffing of the cymbal surface.

A further object of the invention is to provide apparatus which buffs mechanically and uniformly and eliminates the risk of uneven application of pressure to the cymbal surface which generally occurs when the buffing is performed manually.

A still further object of the invention is to provide such apparatus which insures that the pressure applied by the buffer to the cymbal surface is of the proper magnitude.

Yet another object of the invention is to provide novel and improved cymbals which have the shiny and pleasing appearance characteristically produced by buffing but which retain all their prebuffing characteristics unimpaired.

The invention features a method for buffing the surface of a percussion instrument which is constructed of metal and the quality of which may be impaired by heating to an elevated temperature or by removing surface metal therefrom, the surface having a plurality of substantially circular grooves formed therein. The method includes the step of bringing the surface of the instrument and a buffing surface, moving at high speed, into contact for a period of time, which is preferably less than 1 minute and of the order of 15 to 35 seconds, at a predetermined pressure to producefriction between the surfaces during the period of time; the buffing surface is arranged to become deformed locally to exert the pressure substantially uniformly across the entire surface of the instrument substantially simultaneously and to effectively buff the surface of the instrument when the buffer surface is in contact with the surface of the instrument, and the friction during the period of time is insufficient to raise the temperature of the metal sufficiently to affect the tonal quality of the instrument and insufficient to remove a significant amount of the metal therefrom. In preferred embodiments the method'also includes the steps of monitoring the pressure exerted by the buffing surface across the surface of the instrument, adjusting the pressure which is monitored into conformity'with the predetermined pressure, and rotating the surface of the instrument relative to the buffing surface for uniformly buffing the surface of the instrument.

In another aspect the invention features a percussion instrument, such as a cymbal, constructed of metal and having a plurality of substantially circular grooves formed in the surface thereof. The surface has the highly polished appearance characteristic of buffing and the metal retains the tonal qualities characteristic thereof prior to buffing.

In yet another aspect the invention features apparatus for buffing the surface of a percussion instrument constructed of metal, the quality of which instrument may be impaired by heating to an elevated temperature or by removing surface metal therefrom and the surface of which has a plurality of substantially circular grooves formed therein. The apparatus includes buffing means with a buffing surface moving at high speed, pressure applying means arranged to bring the surface of the instrument and the buffing surface into contact for a short period of time preferably at a predetermined pressure to produce friction between the surfaces during that period of time and the buffing surface is arranged to become deformed locally to exert the pressure with substantial uniformity across the entire surface of the instrument substantially simultaneously when the buffing surface is in contact with the surface of the instrument, the friction during that period of time being insufficient to raise the temperature of the metal sufficiently to affect the tonal quality of the instrument and insufficient to remove a significant'amount of metal therefrom.

Other objects, features and advantages of the invention will become apparent from the following description of a preferred embodiment of the invention, taken together with the attached drawings thereof, in which:

FIG. 1 is a view in side elevation of apparatus constructed in accordance with the invention;

FIG. 2 is a top elevation, taken along line 2-2 of FIG. I, of a portion of the apparatus shown in FIG. 1;

FIG. 3 is an enlarged sectional view, taken along line 3-3 of F IG, 1, showing a portion of a cymbal and the tonal grooves cut therein; and

FIG. 4 is a sectional view, taken along line 4-4 of FIG. 2 and partly broken away, showing a portion of the frame supporting the cymbal and the surface which the buffing wheels present to the cymbals after the buffing cloths therein have spread.

Referring to FIG. 1, there is shown an hydraulic hoisting apparatus, generally designated 10, having a movable stand 12 which is arranged to be moved vertically toward rotary buffer 13 a distance determined by an attendant who operates conventional manual controls. Mounted on stand 12 is a wooden frame 14 which is provided with a convex upper portion 15 and arranged to support a cymbal 16 in close proximity thereon and to be rotated at a relatively slow constant speed on shaft 18 by motor 20 through gear assembly 22. Cymbal 16 has a slightly bowed hub portion 24 and a raised cupped center portion 25 with circular center opening 26 which is arranged to receive square peg 30 on frame 14 with a tight fit. Hub portion 24 (FIG. 3) has a plurality of radially spaced substantially circular tonal grooves 27, separated by projecting portions 28, cut in the upper and lower surfaces 29 thereof. Generally, the depth and spacing of grooves 27 vary on the surfaces of each individual cymbal 16 and in many cases grooves are cut in only one ofthe surfaces.

Rotary buffer 13 includes a buffer arbor or shaft 34, having a longitudinal axis which passes over the center of supported cymbal 16, and which is rotatably mounted at one end above frame 14 in bearings in the casing of a motor 40 on a support 38. The motor, which may be a horsepower, 220 volt AC motor is directly connected to the shaft 34 to rotate the same. Ammeter 43 is provided to monitor the current drawn by motor 40. A plurality of buffing wheels, generally designated 44, having varying diameters decreasing toward the center of buffer 13 and which may be approximately 1 inch wide, and comprise a plurality of disc-shaped cloths sewn together at varying distances from their outer periphery to provide flexi ble outer portions, are clamped on arbor 34 between nuts 42 at a spacing of one-fourth inch to three-fourths inch apart. Preferably, the cloths employed are of the soft buff (for example, No. 2 bias buff" cloths sold by M E. Baker Company of Cambridge, Massachusetts) variety with the exception of the cloths from which the outer wheels 46 are fabricated. It will be understood, of course, that the number of wheels 44 on arbor 34 may vary considerably depending upon the diameter of the cymbal to be buffed and that given the spacing between wheels 44 and 46 their number is chosen so as to cover the entire diameter D of cymbal 16. Wheels 46 are constructed of stiffer cloths than those in wheels 44 in order to prevent excessive spreading of the wheels between them.

As is best shown in FIGS. 1 and 2, when the cloths are not in contact with cymbal 16, the buffing wheels are formed to provide a bowed-in shape for the overall outline of the buffing assembly. This shaping may be performed by raking the wheels with a steel comb to comb away the excess cloth or preferably by coating the surface of a shaping" cymbal with an aluminum oxide composition and pressing the shaping cymbal against the wheels 44 and 46, while they are rotated by arbor 34 until the excess cloth is worn away.

The outer edges of the cloths in each wheel 44 are arranged to bend, to come into initial contact with the adjacent cloths in adjacent wheels 44 and 46, and to form a substantially smooth surface (see FIG. 4) having the curved shape complementary to the upper surface 29 of cymbal 16 when cymbal i6 is pressed against wheels 44 and 46 with a predetermined pressure (the selection of which is discussed below).

In operation, a cymbal 116 is mounted on square peg 30 of frame 14. Motors 20 and 40 are started to rotate respectively frame 14 and arbor 34. The attendant operates the manual controls and hoisting apparatus moves stand 12 and, therefore, cymbal l6 vertically toward rotary buffer 13. Liquid buffing compound is cyclically sprayed onto wheels 44 and 46 either manually with a spray gun or automatically. Stand 12 and cymbal 16 continue to move upwardly and cymbal 16 comes into contact with buffing wheels 44 and 46.

As cymbal 16 comes into more intimate Contact with wheels 44 and 46 the drag opposed to rotation of arbor 34 increases and the additional torque required to be produced by motor 40 to maintain the speed of rotation of arbor 34 causes the current drawn by motor 40 to increase. For the 5 horsepower, 220 volt motor used in this embodiment the current drawn by motor 40 when it is idling is generally 10 to amperes. Through experimentation I have found that the optimum pressure of cymbal I6 against wheels 44 and 46 occurs when the additional applied torque required to overcome the drag and to maintain the speed of rotation of arbor 34 at 3,500 rpm. results in an increase in the current drawn by motor 40 to approximately 35 amperes. Thus, the attendant may determine when the pressure is optimal by observing the reading of ammeter 43 as the cymbal is being lifted by hoist l0 and stopping the hoist when the current indicated by ammeter 43 is 35 amperes.

When the cymbal I6 is in the optimum position against the buffing wheels 44 and 46, the cloths in wheels 44 are spread apart laterally and touch the adjacent cloths in the adjacent wheels to present a solid buffing surface with substantially no overlap of cloths.

As is best shown in FIG. 2, if cymbal 16 remained stationary, rotary buffer 13 would not come into contact with two portions of cymbal 116. Thus, provision has been made for rotation of cymbal 16 by rotating shaft 11*} to insure that all of surface 29 of cymbal 16 is uniformly buffed. The fit of square peg 30 in the center opening of cymbal l6 insures that the cymbal does not slip" relative to frame 14. A predetermined time, preferably less than a minute, after the indicated current has reached 35 amperes, the attendant lowers the hoist and removes cymbal 16 from peg 30.

While it is preferred to provide a constant controlled rotation for the support this is not essential. If the cymbal is loose on the support, for example, if peg 30 is cylindrical, it has been found that enough rotation of the cymbal relative to the support is produced by unbalanced frictional forces applied by the buffing wheels at opposite sides of its center to produce complete buffing in most cases.

Since the cymbal 16 is in contact with wheels 44 and 46 for such a short period of time, the tin-copper alloy from which it is cast is not raised to an excessive temperature (which for some alloys may be a temperature between F. and 200 F.) by friction between the cymbal l6 and the buffer wheels 44 and 46. Apparently, the air spaces formed between the outer portions of the cloths when they are flexed permit suffi cient heat to be conducted away from the cymbal to prevent the metal from overheating which would occur even in the short time involved if the buffing wheels were not spaced. In addition, while a slight amount of wear of metal from the cym bal surface occurs, the amount of metal so removed is insig nificant and insufficient to affect the tonal quality of the cymbal.

My experiments have shown that for the particular embodiment described, if the pressure between cymbal l6 and buffer wheels 44 and 46 is increased to a value significantly above that corresponding to the 35 ampere reading of the ammeter, excessive heating and/or excessive wear may occur. Alterna tively, if the pressure is permitted to decrease significantly e.g., below that corresponding to a reading of 30 amperes the pressure is generally insufficient to buff the surface of cymbal l6 properly. The attendant, by observing the reading of ammeter 43 and by making appropriate adjustments of the position of hoist it) if the current drawn by the motor falls outside of the 30-35 ampere ranges during the buffing operation, may maintain the pressure at an acceptable value. If desired, this function may be performed automatically by suitably connecting the pressure monitor, such as ammeter 43, to the pres sure actuation system of the hoist.

The illustrated embodiment is adapted to buff only the convex face of the cymbal. To buff also the concave face a second machine may be utilized which is the same as that illustrated except that the shape of the support is correspondingly concave and the transverse shape of the buffing wheel assembly is correspondingly convex from the ends to the middle.

lclaim:

l. A method for buffing the convex or concave surface of a metal percussion instrument such as a cymbal which has a plurality of substantially circular grooves formed therein about its center, the strength and tonal qualities of which instrument are impaired by heating to an elevated temperature and by removing substantial surface metal therefrom, said method comprising:

causing a buffing surface having a curved shape throughout its extent complementary to the shape ofthc surface to be buffed rotating at high speed to apply effective buffing prises a plurality of buffer wheels carried on a shaft rotating at high speed,

said buffer wheels being arranged to deform locally to define said buffing surface having a shape which is substantially identical with the shape of said surface of said instrument for exertion of said pressure with substantial uniformity across said surface of said instrument.

4. The method of claim 3 wherein each of said buffer wheels comprises a plurality of flexible cloth discs carried on said shaft, having an outer circumferential portion,

said outer portion of said discs being deformable locally to define said bufiing surface.

5. The method of claim 4 wherein said buffer wheels are spaced apart by a distance of the order of one-fourth to threefourths inch and said pressure is such as to deform the outer portion of said discs to spread across the spaces between said wheels. 

1. A method for buffing the convex or concave surface of a metal percussion instrument such as a cymbal which has a plurality of substantially circular grooves formed therein about its center, the strength and tonal qualities of which instrument are impaired by heating to an elevated temperature and by removing substantial surface metal therefrom, said method comprising: causing a buffing surface having a curved shape throughout its extent complementary to the shape of the surface to be buffed rotating at high speed to apply effective buffing pressure substantially uniformly and for a uniform period of time substantially simultaneously to said entire instrument surface while rotating said instrument about its center, and preventing impairment of said qualities of said instrument by limiting said period of time to less than 1 minute.
 2. A method according to claim 1 wherein said period of time is of the order of 15 to 35 seconds.
 3. The method of claim 1 wherein said buffing surface comprises a plurality of buffer wheels carried on a shaft rotating at high speed, said buffer wheels being arranged to deform locally to define said buffing surface having a shape which is substantially identical with the shape of said surface of said instrument for exertion of said pressure with substantial uniformity across said surface of said instrument.
 4. The method of claim 3 wherein each of said buffer wheels comprises a plurality of flexible cloth discs carried on said shaft, having an outer circumferential portion, said outer portion of said discs being deformable locally to define said buffing surface.
 5. The method of claim 4 wherein said buffer wheels are spaced apart by a distance of the order of one-fourth to three-fourths inch and said pressure is such as to deform the outer portion of said discs to spread across the spaces between said wheels. 